The main function of BIOS (Basic Input Output System) is to initialize the hardware of a computer system while a user power on the computer system. That is, the boosting procedure is first executed by the computer system based on a plurality of parameters of the BIOS while the user pushing the power button of the computer system. Basically, the BIOS parameters are stored in a CMOS (Complementary Metal Oxide Semiconductor) that is arranged on a motherboard of the computer system, where CMOS is a RAM (Random-Access Memory) and requires less power than other types of memories.
After the power button of the computer system is pushed, a POST (Power-On-Self-Test) program is executed. The user can set the BIOS parameters during the process of executing the POST. That is, a BIOS-SETUP interface is brought after the user pressing some specific functional keys, such as “Del” or “Alt+Ctrl+Esc” while the POST is executing, and the user can set the BIOS parameters via the BIOS-SETUP interface. The BIOS parameters, stored in the CMOS RAM, are some essential date or information about the computer system, such as the types and specifications of IDE, the operation frequency of CPU, or the type and capacity of the memory. Because these BIOS parameters are so important, the computer system cannot be successfully boosted without these BIOS parameters. To guarantee all these BIOS parameters will not be lost after a shutdown of the computer system, the CMOS RAM stored with the BIOS parameters must be powered by a RTC (Real-Time Clock) battery, where the RTC battery is also arranged on the motherboard but is independent of the power source of the other parts in the computer system. In other words, the RTC battery can always provide power to the CMOS RAM even the computer system is shutdown, so as the BIOS parameters stored in the CMOS RAM can be always kept.
As described above, the BIOS parameters can be set by the user via the BIOS-SETUP interface. Once the BIOS parameters are set again, the computer system will start to process the boosting procedures based on the updated BIOS parameters after the user pushing the power button of the computer system next time. However, the user may set wrong parameters. Once the user sets wrong some important BIOS parameters, such as the operation frequency of CPU, a boost failure of the computer system or a startup failure of the monitor may be happened.
Once the startup failure of monitor is occurred, the user has no way to correct the BIOS parameters, because the monitor cannot display messages on the screen. However, the user still can restore the initial BIOS parameters back to the computer system via erasing the CMOS RAM, and then the computer system will start to process the boosting procedures based on the initial BIOS parameters after the user pushing the power button of the computer system next time.
FIG. 1 is a block diagram of a conventional motherboard of a computer system. The motherboard 10 comprises a CPU (Central Processing Unit) 101, a north bridge 103, a south bridge 105, a CMOS RAM 107, a RTC battery 109, and a pin set 111, where the BIOS parameters are stored in the CMOS RAM 107; the CMOS RAM 107 is powered by the RTC battery 109; and the pin set 111 includes three pins (#1, #2, #3).
The initial BIOS parameters can be restored back to the computer system via changing connection of the three pins (#1, #2, #3) 111. Firstly, the user must enforce to shutdown the computer system. Because the computer system cannot enter to the operation system (OS) due to the failure of the execution of BIOS, user can enforcedly shutdown the computer system via continuously pressing the power button of the computer system over four seconds (4-second shutdown) or directly plugging out the power line of the computer system. After the shutdown of the computer system, the user then changes connection of the jumper to pins (#2, #3) from pins (#1, #2). Several seconds later, the user again changes the connection of the jumper back to pins (#1, #2) from pins (#2, #3). The object of shortly moving the jumper to pins (#2, #3) is to make a short circuit between the pins (#2, #3), and once the pins (#2, #3) are short circuit, a CMOS-erasing signal (RTCRST#) is pulled down to a low level and is transmitted to CMOS RAM 107 from the south bridge 105. After the CMOS-erasing signal (RTCRST#) with a low level is transmitted to the CMOS RAM 107, the CMOS RAM 107 is erased, so as the initial parameters (data, time, system parameters) are restored back to computer system. Then, the user can press the power button of the computer system; accordingly the computer system will start to process the boosting procedures based on the initial BIOS parameters.
Or, the initial BIOS parameters can be restored back to the computer system via temporarily removing the RTC battery 109 from the motherboard 10. Firstly, the user can enforcedly shutdown the computer system via continuously pressing the power button of the computer system over four seconds (4-second shutdown) or directly plugging out the power line of the computer system. Afterwards, the user removes the RTC battery 109 from the motherboard 10 for several seconds, and then attaches the RTC battery 109 back to motherboard 10 again. Because the CMOS RAM 107 is directly powered by the RTC battery 109, the CMOS RAM 107 will be erased while the RTC battery 109 is temporarily removed from the motherboard 10 for several seconds, so as the initial BIOS parameters are restored back to the computer system. Then, the user can press the power button of the computer system; accordingly the computer system will start to process the boosting procedures based on the initial BIOS parameters.
However, no matter restoring the initial BIOS parameters back to the computer system via the pin set 111 or via temporarily removing the RTC battery 109 from motherboard 10, the user must dismantle and reassemble the case of the computer system and thus is inconvenient.